The infrared seeking missiles currently in use utilize irdomes of germanium and optical elements to correct aberrations introduced by the irdome. The aerodynamic shape of the irdome is limited by the optical considerations. Holographic optical elements can overcome these limitations by correcting aberrations even from aerodynamically improved irdomes.
Holographic optical elements, HOE's, can be used for many purposes including correcting elements behind missile domes, lenses, and gratings. HOE's in the visible are used for gratings and other optical elements. Similar infrared, IR, transparent HOE's are desired but have not been made previously. A phase hologram can be made in polymer film if index of refractions gradients can be formed on a scale comparable to the wavelengths of light.
The advantages of such HOE films over conventional optical elements are reduced weight and cost. Conventional infrared optics require special glass of germanium or magnesium floride which needs to be ground to the proper shape.